Hydraulically lifted concrete form systems for elevator cores are presently known and used on building construction sites. In leveling these hydraulically lifted concrete forms from floor to floor, several systems are presently used, and they each have significant drawbacks.
The first known raising system utilizes water levels. The problems with water levels are that they must be maintained and serviced prior to every lift to be sure they are operational. The accuracy of the lift is determined by the operator of the system. The accuracy of how even the form is lifted is dependent on how quickly the water levels respond in the tubes and how quickly the operator responds to variances. Often times the operator will ignore or not be aware of variances that can be critical to the loading of major form components creating an unsafe condition.
The water lines used in a water leveling system can often become kinked and/or clogged causing the readings to be incorrect. During winter conditions, precautions have to be taken to be sure that the water or other liquid in the lines does not freeze. In summer conditions, the water or other liquid in the lines can evaporate, requiring the operator to top off the liquid prior to starting. Because of the length of the water lines and the routing that often times must be taken, the lines are prone to damage. All these factors contribute to inaccuracy in the lifting process. Frequently the water levels are ignored, and the concrete form is lifted with no leveling assistance.
A second type of system used to coordinate lifting the system involves having men located at each of the critical lifting points to physically measure the progress of the lift from the previous pour as it progresses. The progress is often shouted out to the operator or communicated via radio. The operator analyzes what each of the measurements mean and turns the power units on or off accordingly. The system is very labor intensive and inaccurate requiring many men to measure at once and is only as accurate as the men doing the physical measurement and the ability of the operator to analyze the information and respond quickly to it.
A third method depends on the operator's ability to sense that the concrete form is rising. In this method, the operator uses reference structures that are close by to coordinate the rise of the system. This method is the most inaccurate since no actual measuring devices are used.
A fourth method depends on the repeatability of mechanical pump valves or sensors. This method operates on the theory that if all cylinders are pumped an equal volume, they will all ascend equally. This is often not true because the equipment used cannot guarantee repeatability. For instance, there may be leakage in the system or there may be variances in the construction of the items employed in the lift. The number of hydraulic cylinders coordinated at once is limited.
Monitoring the system in order to achieve the desired lift height on all four systems depends on a physical measurement by the operator or a helper of the operator.
The present inventors recognize a need for a form control and monitoring system that coordinates all hydraulic cylinders quickly, safely and precisely.